KR20110130295A - Apparatus for recovery of ruthenium and method for the same - Google Patents

Abstract

PURPOSE: A device for recovery of ruthenium and a method for the same are provided to reduce costs for a separate chlorine containing system and supplying device by producing hydrochloric acid gas using the electric chemistry reaction. CONSTITUTION: A device for recovery of ruthenium comprises a chlorine electrolysis production tub, a leaching tank, a cooling device, a collector and a chlorine recycle line. The chlorine electrolysis production tub comprises a cathode chamber, an anion exchange film and an anode chamber. The chlorine electrolysis production tub establishes the respective electrode in the anode chamber and cathode chamber. The electrode is composed of the insoluble conducting material which is stable in the electro chemical reaction. The cathode chamber and anode chamber comprise graphite, iridium or ruthenium coating titanium electrode. The leaching tank comprises ozonizer and pH controller. The cooling device is connected to the leaching tank. The collector collects the ruthenium oxide in the backend of the cooling device. The chlorine recycle line sends the hydrochloric acid gas, remaining in the leaching tank, to the chlorine electrolysis production tub.

Description

Ruthenium recovery device and ruthenium recovery method using the same {Apparatus for recovery of ruthenium and method for the same}

The present invention relates to a ruthenium recovery apparatus, a ruthenium recovery method using the same, and more particularly, the chlorine gas generated in the chlorine electrolytic generation tank reacts with ruthenium in the leaching tank to leach ruthenium or ruthenium content and recover it from the collection tank. And a ruthenium recovery method using the same.

Ruthenium metal is used in the manufacture of lumoring, a ruthenium and molybdenum alloy in powder or sponge form, and is used as an electrode of a microwave oven, and part of it is used as a resist paste as ruthenium oxide. Ruthenium pastes, including ruthenium dioxide forms, are used as black pastes for varistors, semiconductor chip resistors and PDPs.

Ruthenium compounds are mainly used ruthenium trichloride, which can be divided into fuel cells and insoluble electrodes. Ruthenium trichloride, used for fuel cells, is used to make carbon ruthenium electrodes containing about 40% ruthenium. Ruthenium is applied to petrochemical catalysts to increase the octane number in the manufacture of various petroleum compounds and crude oil refining. Mainly used petrochemical reforming catalysts are Ru / C and Ru / Al ₂ O ₃ catalysts. These catalysts contain about 1% ruthenium. Ruthenium has increased demand as it has chemical and heat resistant catalyst characteristics with the development of the domestic electronic and petrochemical industries, and it is used for electrical contact materials, ultra high temperature thermoelectric materials, ultra high strength materials, and solar cell catalyst materials, but it is unstable supply and High price is formed due to absolute overseas dependence, and supplier-centered price formation is a big problem.

Conventional ruthenium recovery technology uses INCO's high-temperature sealed system to produce halogen compounds (300 ℃ -F ₂ reaction, 600 ℃ -Cl ₂ reaction) by using HCl / Cl ₂ INCO process and chemical reaction. There is a process of chemically activating and separating.

There is also a method of using sodium hypochlorite (NaClO), a method of using potassium periodate (KIO ₄ ) and a method of using potassium permanganate (KMnO ₄ ) in the sulfuric acid atmosphere. In the method using sodium hypochlorite, ruthenium is oxidized to Na ₂ RuO ₄ in an alkali excess NaClO solution. When alkali is not added Na ₂ RuO ₄ is oxidized and the 2NaRuO ₄ is the use of ruthenium oxide RuO _4. This method has the disadvantage of having to carry out the reaction using a high concentration of sodium hypochlorite solution and of continuously supplying chlorine to the system for generating RuO ₄ directly in the reactor. In addition, repeated cooling, alkali feeding and repeated saturation steps can lead to corrosion problems in the installation due to the long time and use of chlorine gas. The method of using potassium periodate is a method of producing RuO ₄ by oxidizing with potassium periodate in neutral or acidic conditions. A disadvantage of this method is that it cannot precipitate metal ruthenium with potassium periodate. The method of using potassium permanganate in the sulfuric acid atmosphere is likely to cause impurities due to the possibility of precipitation of manganese dioxide if the acidic environment becomes insufficiently acidic while distilling ruthenium.

As such, ruthenium is a rare platinum group and has a commercial value due to its high price, but one of the poorly soluble platinum group metals has a complicated process, and it is difficult to leach due to corrosion problems due to chlorine gas.

The present invention is to solve the problems of the prior art by generating a chlorine gas by using an electrochemical reaction in the chlorine electrolysis tank so that chlorine gas can be used only when necessary to store and supply a separate chlorine for use of chlorine gas The present invention provides a ruthenium recovery apparatus and a ruthenium recovery method using the same.

The ruthenium recovery device is a closed system that can be used to recycle chlorine gas (maximum) can maximize the use efficiency of chlorine gas, it is possible to solve the problem of corrosion of the equipment by chlorine gas and ozone gas. More specifically, the present invention generates chlorine gas in the chlorine electrolytic generation tank, leaches ruthenium by reacting the chlorine gas with ruthenium in the leaching tank at the rear end of the chlorine electrolytic production tank, and adjusts the pH of the solution in which the ruthenium is dissolved. The present invention provides a ruthenium recovery apparatus that volatilizes the produced ruthenium tetraoxide to remove impurities through a cooler connected to a leaching tank, and then collects ruthenium trichloride in a collection tank. In particular, the chlorine gas remaining in the leaching tank at the time of dissolution to the chlorine electrolytic production tank through the chlorine recycling line to reduce it electrochemically to the chloride ion and to reuse it in the production of chlorine gas ruthenium recovery device and It relates to a ruthenium recovery method using the same. In addition, the above object of the present invention can be achieved by providing the optimum conditions of factors including pH, temperature and applied current in the dissolution step of leaching ruthenium and the volatilization step.

The present invention provides a ruthenium recovery apparatus and a ruthenium recovery method using the same, wherein the ruthenium recovery apparatus comprises a chlorine electrolytic generation tank; A leaching tank for leaching ruthenium or ruthenium content at the rear end of the chlorine electrolytic production tank; A cooler connected to the leaching tank; A collecting tank for collecting volatile ruthenium oxide at a rear end of the cooler; And a chlorine recycling line for sending the chlorine gas remaining in the leaching tank to the chlorine electrolytic generation tank.

The chlorine electrolytic generation tank includes a cathode chamber, an anion exchange membrane, and an anode chamber, and the cathode chamber and the anode chamber include graphite, iridium, or ruthenium oxide coated titanium electrodes. The anion exchange membrane may be used as long as it can prevent the mutual influence of the reaction between the two electrodes of the cathode chamber and the anode chamber as a separator.

The chlorine electrolytic generation tank includes a hydrochloric acid solution, and electrolytic reaction is generated by applying a current or voltage through the electrode to generate chlorine gas. This can alleviate the burden of additionally installing a storage tank or a device for continuously supplying chlorine gas to prevent the leakage of gas by continuously providing a separate storage tank for supplying chlorine gas. In addition, the chlorine gas obtained by the electrolysis reaction of the present invention can be stably supplied to the leaching tank, the trace amount of chlorine gas not reacted in the leaching tank is circulated back to the cathode chamber of the chlorine electrolytic production tank through the chlorine recycle line, which is After reduction to chloride ions is moved to the anode chamber through the anion exchange membrane to be reused in the chlorine production reaction has the advantage that can maximize the chlorine utilization efficiency. The supply of chlorine gas by the electrolysis can completely block the risk of leakage due to the supply of chlorine gas from the outside, and can be said to be an important factor in ruthenium recovery because there is no burden on facility corrosion.

The chlorine gas generated in the chlorine electrolytic generation tank enters the leaching tank through the connected pipe. The leaching tank undergoes a dissolution step of leaching ruthenium by the reaction between chlorine oxidant and ruthenium and a volatilization step to volatilize it and send it to the collection tank.

The dissolution step and the volatilization step leaches and evaporates ruthenium by adjusting the pH. Thus, the leaching tank is equipped with a pH controller for pH control. The pH controller uses an aqueous alkali solution such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, and the pH in the dissolution step is preferably adjusted to 10 to 14. If the pH is less than 10, the leaching of ruthenium is not progressed smoothly, and if it exceeds 14, excess alkali is consumed and economic efficiency is low. Chlorine pH from 10 to a pH region of 14. The primary oxidant OCl for ruthenium leach ^- and is present, the acid agent (OCl ^-) in the pH range RuO4 ² reacted with a ^{ruthenium-while} present in the ionic form solution leaching Will be. Equation 1 below shows the reaction of chlorine gas and water in the pH range in the aqueous solution to produce a chlorine oxidant (OCl ⁻ ) in the dissociated state of HOCl, Equation 2 is a reaction of the produced chlorine oxidant and ruthenium It is shown. ΔG _o of ruthenium leaching in the following formula 2 The value is -74.765 kcal, which allows the leaching of ruthenium oxide as a spontaneous reaction occurs. In addition, the temperature conditions in the dissolution step are also important. The temperature is preferably maintained at 20 to 90 ℃. Ruthenium leaching is not smoothly out of the temperature range it is preferable to have a thermostat for maintaining this temperature.

_{(1) Cl 2 + H 2} O → 2H + + Cl - + OCl -

^{(2) Ru + 3OCl - +} H 2 O → RuO 4 2 - + 2H + + 3Cl -

In the dissolution step, ruthenium is dissolved in a leaching tank in the form of RuO ₄ ^{2 -} and undergoes a volatilization step in which the dissolved ruthenium is moved to a collection tank.

The volatilization step changes the state of ruthenium from RuO ₄ ^{2 -} to RuO ₄ ^- to RuO ₄ gas state by adjusting the pH to 3 to 10. By naturally moving it to the collection tank, it is collected as ruthenium trichloride, the final product. If it is out of the pH range in the volatilization step, the ruthenium oxide does not volatilize well, and it is difficult to capture ruthenium trichloride of high purity because a large amount of impurities of the volatilized ruthenium oxide are present.

The condition for changing the ruthenium into a gas state is preferably carried out by simultaneously adding chlorine gas and ozone, which are existing oxidants. Ozone has the property that the third atom of the three atoms is weakly separated and easily separated into generator oxygen. Since the oxidative decomposition of oxygen has a oxidizing power six times stronger than that of chlorine, ozone gas is added to ruthenium to form a gas. It can be easy to change. Therefore, the leaching tank is preferably provided with an ozone generator capable of supplying ozone gas. The supply amount of ozone gas generated in the ozone generator is preferably 0.08 to 0.5g / h, and supplying ozone gas within the above range increases the moving speed of RuO ₄ changed into a gas state to act as a catalyst for volatilization. .

In addition, the temperature in the volatilization step is preferably maintained at 20 to 90 ℃. Outside the above temperature range, it is difficult to volatilize ruthenium oxide.

The ruthenium oxide passed through the volatilization step is passed through a cooler connected to a leaching tank. Through the condenser while volatilized as ruthenium oxide on Na ^+, to remove the salt ions such as H ⁺ it can be collected by being of high purity ruthenium trichloride twos collected. The cooler serves to sort and purify using a cooling capacitor, and prevents impurities from moving to the collection tank together with the water.

Figure 1 is a schematic view of the ruthenium leaching reaction, as shown the ruthenium recovery device of the present invention is a chlorine electrolyte generation tank, a leach tank at the rear end of the chlorine electrolyte production tank, the leaching tank is provided with a pH regulator and an ozone generator, connected to the leaching tank It is a closed type system including a cooler, a collecting tank at the rear end of the cooler, and a chlorine recycling line capable of recycling chlorine gas remaining in the leaching tank to a chlorine electrolytic production tank.

The hermetic system includes a system capable of maximizing the utilization rate of chlorine gas by recycling chlorine gas and recycling it, and blocking the light to obtain high purity ruthenium trichloride. This is to ruthenium is present in other species, depending on pH, pH 12 or more in the stand to the stand orange RuO ₄ ^2- (Ruthenate) as a black solid _{RuO 2 2H 2 O (Ruthenic oxide} ) and green in accordance with RuO ₄ oxidation ^- present in a (Perruthenate), and the pH 12 or less RuO _{^4-exist in, RuO 2 2H 2 O, RuO} 4. At pH 12 or higher, RuO ₄ ⁻ is unstable, oxidizes H ₂ O molecules, liberated with oxygen and RuO ₄ ^{2 −} , and reacts as shown in Equation 3 below. Below pH 12, the reaction is reduced to RuO ₂ 2H ₂ O as a black solid. In addition, below pH 7.5, RuO ₄ ⁻ is changed to unstable volatile yellow RuO ₄ or H ₂ RuO ₅ as shown in Equation 5 below. At this time, H ₂ RuO ₅ quickly decomposes to RuO ₂ 2H ₂ O when exposed to light. Since RuO ₂ is not stable in the ionic state after being produced in a stable solid state, the system is a sealed type that can block light. desirable.

^{_{(3) 4RuO 4 - + 2H}} 2 O → 4RuO 4 2 - + O 2 + 4H +

^{_{(4) RuO 4 - + 4H}} + + 3e - → RuO 2 2H 2 O

_{(5) RuO 2 + 3H 2} O → H 2 RuO 5 + 4H + + 4e -

Ruthenium recovery method in the present invention comprises the steps of electrolytic generation of chlorine by applying a current or voltage to the chlorine electrolytic generation tank;

Dissolving the chlorine into a leaching tank to leach ruthenium or ruthenium content; Volatilizing the leached ruthenium with ruthenium tetraoxide; Purifying the volatilized ruthenium oxide in a cooler; And a collecting step of collecting the purified reactant in a collecting tank.

The dissolution step includes sending the remaining chlorine gas to the chlorine electrolyte production tank through the chlorine recycle line, the pH in the dissolution step is characterized in that it is made at 10 to 14, 20 ~ 90 ℃.

The volatilization step is a step to volatilize the ruthenium dissolving product naturally into the collection tank through the dissolution step, the pH is 3 to 10, characterized in that made at 20 ~ 90 ℃.

The collecting step is a step of reducing ruthenium volatilized with ruthenium tetraoxide in a collection tank to form ruthenium trichloride, while supplying ruthenium tetrachloride into a solution in which chloride ions and a reducing agent are mixed at room temperature (25 ° C.) or less, preferably 5 Characterized in that the collection is made of ruthenium trichloride at ~ 25 ℃. Hydrochloric acid solutions with a pH of 1 or less are advantageous as the chloride ion source, and as a reducing agent, ethanol, methanol, isopropanol, or the like may be used as an organic compound such as alcohol to prevent contamination of metal impurities.

In the present invention, since the chlorine gas is generated by using an electrochemical reaction, a device for supplying chlorine gas to the outside, a facility for preventing gas leakage of the gas supply device, and a continuous supply of chlorine gas, compared to a process for directly blowing chlorine gas. The cost is reduced and the process is simple because the burden of additional installation of the storage device for the system is eliminated. In addition, the chlorine gas obtained by the electrolysis reaction of the present invention can be stably supplied to the leaching tank, and the chlorine gas not reacted in the leaching tank is circulated back to the chlorine electrolytic generation tank through the chlorine recycling line to reuse the chlorine gas generation. In addition to maximizing chlorine utilization efficiency, ruthenium recovery reaction can completely block the risk of equipment corrosion and gas leakage.

In addition, in the present invention, in obtaining ruthenium trichloride, the leached ruthenium is converted into a gaseous state having a volatility and collected in a collection tank, so that other impurities are not included in the ruthenium trichloride solution, thereby obtaining high purity ruthenium trichloride.

1 is an aspect of a ruthenium recovery apparatus.
2 is a graph showing the leaching rate according to pH concentration during ruthenium leaching.
3 is a graph showing the leaching rate according to the reaction temperature during ruthenium leaching.
4 shows ruthenium trichloride EDS analysis results prepared by crystallizing at 120 ° C. for 24 hours.

Hereinafter, the present invention will be described in detail by way of examples.

However, the following examples are illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

1 is an example showing a ruthenium recovery apparatus according to the present invention. As shown in FIG. 1, a ruthenium recovery apparatus according to the present invention includes a chlorine electrolytic generation tank having an anode chamber, a cathode chamber, and a separator; A leaching tank for leaching ruthenium at a rear end of the chlorine electrolytic generating tank; A cooler connected to the leaching tank; A collecting tank for collecting ruthenium oxide at a rear end of the cooler; It is configured to include.

The chlorine electrolytic generation tank is provided with an electrode in the anode chamber and the cathode chamber, respectively, the separator is provided therebetween. The electrode is composed of an insoluble conductive material that is stable to an electrochemical reaction, and the kind thereof includes titanium and graphite, and preferably, a graphite, iridium, or ruthenium-coated titanium electrode which is stable to chlorine oxidizing agents. The separator is provided to exclude the mutual influence of the two electrode reactions, it is preferable to use an anion exchange membrane. The chlorine electrolytic production tank configured in this way may be any material that has corrosion resistance in the oxidation of chlorine such as acrylic and glass.

The chlorine electrolytic generating tank is used to generate chlorine gas by electrolysis by an electrochemical reaction, using hydrochloric acid as an electrolyte. The chlorine gas generated in the chlorine electrolytic generation tank enters the ruthenium leaching tank installed at the rear stage.

The leaching tank maintains a constant temperature using a constant temperature circulation tank, it can be adjusted to maintain a constant pH using a pH controller. The pH regulator is adjusted using a sodium hydroxide solution.

In the leaching tank, a leaching sample containing ruthenium is introduced and reacts with chlorine gas generated in the chlorine generating tank to leach ruthenium.

Through the following examples it can be confirmed the optimum conditions for improving the leaching rate of ruthenium.

(Example 1)

The solution used in the chlorine electrolytic bath was prepared using 35% hydrochloric acid from JUNSEI (Japan), 250 mL of ³ molL ^-1 hydrochloric acid solution was used in the anode chamber, and 500 mL of 35% hydrochloric acid solution was used in the cathode chamber. After connecting wires to the graphite electrodes installed in the anode chamber and the cathode chamber, chlorine gas was generated by applying a current. The leaching tank has a ruthenium-based leaching sample and contains an aqueous sodium hydroxide solution. At this time, the pH of the leaching tank was maintained at 8, the applied current was 2A, the temperature was 40 ℃, the reaction time was 60 minutes, the results are shown in FIG. For the collection tank solution, 500 mL of a mixed solution of 6 mol L- ¹ hydrochloric acid (JUNSEI, Japan, 35%) and 20% ethanol (DC chemical, 99.9%) was used.

(Example 2)

Except that the pH concentration in the leaching tank was carried out in the same manner as in Example 1, the results are shown in FIG.

(Example 3)

Except that the pH concentration in the leaching tank was carried out in the same manner as in Example 1, the results are shown in FIG.

Referring to Figure 2, according to Examples 1 to 3, after the reaction time 10 minutes, pH 10, pH 13, pH 8 to 68.56% at pH 8, 88.12% at pH 10, 78.12% at pH 13 The leaching rate was high. That is, at pH 10, the ruthenium leaching rate increased about 20% than pH 8 and about 10% than pH 13. After 60 minutes, the reaction time was 84.34% at pH 10, 76.72% at pH 13, and 69.1% at pH 8. That is, at pH 10, the ruthenium leaching rate increased about 8% than pH 13 and about 15% than pH 8. Therefore, it can be seen that the leaching rate of ruthenium is the highest at high pH 10. The leaching rate was measured as a result of excluding part volatilized with ruthenium tetraoxide after leaching, and the volatilization was higher at lower pH. Except for pH 8 of the solution during leaching, no residue remained after leaching and it was confirmed that the leaching sample of the ruthenium component completely dissolved.

Examples 4 to 6 below confirm the leaching rate according to the reaction temperature in the leaching tank.

(Example 4)

The current applied to the chlorine electrolytic generation tank was 2A, the pH concentration in the leaching tank was 10, the reaction temperature in the leaching tank was 40 ° C, and the results are shown in FIG.

(Example 5)

Except that the reaction temperature in the leaching tank was 20 ℃ was carried out in the same manner as in Example 4, the results are shown in FIG.

(Example 6)

Except that the reaction temperature in the leaching tank is 80 ℃ was carried out in the same manner as in Example 4, the results are shown in FIG.

3, according to Examples 4 to 6, the ruthenium leaching rate was 40 ° C.> 80 ° C. at 20 ° C. (72.46%), 40 ° C. (88.12%), 80 ° C. (75.28%) after 10 minutes of reaction time. In order of 20 ° C. That is, when the reaction temperature is 40 ℃ ruthenium leaching rate was increased by about 16% than 20 ℃, about 13% than 80 ℃. After 60 minutes, the ruthenium leaching rate was 20 ℃ (74.13%), 40 ℃ (84.34%), and 80 ℃ (74.18%) in order of 40 ℃> 80 ℃ ≥ 20 ℃. At 40 ° C, the ruthenium leaching rate increased about 10% above 80 ° C and about 10% above 20 ° C. It is present in the leaching tank as OCl ^- at pH above 10, but the chlorine is added in the form of Cl ₂ (g) in the gaseous state, and heat energy must be supplied to supply the activation energy required for dissolution of the ruthenium leach sample. Increasing the Cl ₂ gas decreases its solubility as the temperature increases, so as the temperature increases, the solubility Cl ₂ is easily volatilized, and as a result, the production of OCl ⁻ by reaction with the solution is reduced. Therefore, it can be seen that the ruthenium leaching rate is high at 40 ° C. when the reaction with the solution of chlorine gas is easy and the appropriate thermal energy is supplied even for the dissolution of the leaching sample. If the leaching step is to be carried out at a high temperature, it is also possible to prepare a solution containing a high concentration of OCl ^- by preliminarily adding chlorine at a low temperature, and then increase the temperature of the solution and then dissolve it by adding a leaching sample. Do.

The ruthenium leached through the above embodiment is volatilized with ruthenium tetraoxide and collected in a collection tank, and it is shown in FIG. 4 that the collected ruthenium trichloride is crystallized. As shown in FIG. 4, ruthenium trichloride crystals can be confirmed that ruthenium and chlorine, which are main elements, account for 99.87% of the total components, and thus are high purity ruthenium trichloride.

In the present invention as described above has been described by the specific matters and the specific embodiments and drawings as shown in the specific device diagram, which is provided only to help a more general understanding of the present invention, the present invention is not limited to the above embodiment. For those skilled in the art, various modifications and variations are possible from such description.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

Claims (8)

Chlorine electrolysis tank; A leaching tank for leaching ruthenium or ruthenium content at the rear end of the chlorine electrolytic production tank; A cooler connected to the leaching tank; A collecting tank for collecting ruthenium oxide at the rear end of the cooler; And a chlorine recirculation line for sending chlorine gas remaining in the leach tank to a chlorine electrolysis generating tank. The method of claim 1,
The leaching tank is a ruthenium recovery device comprising an ozone generator and a pH controller. The method of claim 1,
The system is a ruthenium recovery device, characterized in that the sealed type that can block the light. The method of claim 1,
The chlorine electrolytic generating tank includes a cathode chamber, an anion exchange membrane and an anode chamber, and the cathode chamber and the anode chamber include graphite, iridium or ruthenium coated titanium electrodes. Electrolytically generating chlorine by applying a current or voltage to the chlorine electrolysis generating tank;
Dissolving the chlorine into a leaching tank to leach ruthenium or ruthenium content; Volatilizing the leached ruthenium with ruthenium tetraoxide; Purifying the volatilized ruthenium oxide in a cooler; And a collecting step of collecting the purified ruthenium oxide in a collecting tank. The method of claim 5,
The dissolution step is a pH 10 to 14, ruthenium recovery method characterized in that made at 20 ~ 90 ℃. The method of claim 5,
The volatilization step is a pH 3 to 10, ruthenium recovery method characterized in that made at 20 ~ 90 ℃. The method of claim 5,
The collection step is a ruthenium recovery method, characterized in that made in a solution containing a reducing agent at 25 ℃ or less.

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